(1) Field of the Invention
The present invention relates to a method for use in a case of laminating a substrate for reinforcement onto various kinds of substrates, such as semiconductor wafers, glass substrates, and wiring boards through a double-sided adhesive tape, and to an apparatus using the method.
(2) Description of the Related Art
Semiconductor wafers (hereinafter referred to as “wafer”) are obtained in a manner that the back side of the wafer is ground by a back grinding process after formation of a large number of elements on the wafer, and subsequently the wafer is cut into each element in a dicing process. However, as demand for a higher density packaging increases in recent years, a smaller wafer thickness level from 100 micrometers to 50 micrometers, and furthermore a level of approximately 25 micrometers tend to be needed.
The wafer that has been subjected to back grinding into such a level of thickness may have possible brittleness and distortion, leading to extremely poor handling property.
Accordingly, a method of reinforcement of the wafer by lamination of a substrate having rigidity such as glass plate etc. to a wafer through an adhesive sheet has been proposed.
In detail, a wafer having an adhesive tape beforehand applied on the top face thereof is mounted in a holding stand, and a base made of a glass plate etc. (a supporting substrate for reinforcement) is held at the upper end of a base supporting section in a slanting attitude over this wafer. In this condition, a press roller is moved to the surface of the base, the base supporting section is lowered corresponding to the movement, thereby laminating the base onto the semiconductor wafer (refer to JP-A No. 2000-349136).
For the lamination of the base, a double-sided adhesive tape that has separators attached to front and back adhesion faces thereof is used as an adhesive tape to be joined to the wafer. The adhesion face exposed by separation of one of the separators is joined to the surface of the wafer. Subsequently the adhesive tape is cut along with the contour of the wafer, thereby preparing the wafer to which the double-sided adhesive tape having the separator left on the surface thereof is joined. This wafer is then transported in a laminating apparatus in a different process. Here, a process for laminating the wafer on the base is performed.
In this case, the separator left on the surface of the adhesive tape needs to be separated prior to the laminating process in order to expose the adhesion face for lamination of the base. This separator is manually separated by an operator, leading to difficulty in improvement of workability.